Datasheet

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LAYOUT
DAC8552
SLAS430A – JULY 2006 – REVISED OCTOBER 2006
The power applied to V
DD
should be well-regulated
and low-noise. Switching power supplies and dc/dc
A precision analog component requires careful
converters will often have high-frequency glitches or
layout, adequate bypassing, and clean,
spikes riding on the output voltage. In addition, digital
well-regulated power supplies.
components can create similar high-frequency
spikes. This noise can easily couple into the DAC
The DAC8552 offers single-supply operation, and it
output voltage through various paths between the
will often be used in close proximity with digital logic,
power connections and analog output.
microcontrollers, microprocessors, and digital signal
processors. The more digital logic present in the
As with the GND connection, V
DD
should be
design and the higher the switching speed, the more
connected to a positive power-supply plane or trace
difficult it is to keep digital noise from appearing at
that is separate from the connection for digital logic
the output.
until they are connected at the power entry point. In
addition, a 1 µ F to 10 µ F capacitor in parallel with a
Due to the single ground pin of the DAC8552, all
0.1 µ F bypass capacitor is strongly recommended. In
return currents, including digital and analog return
some situations, additional bypassing may be
currents for the DAC, must flow through a single
required, such as a 100 µ F electrolytic capacitor or
point. Ideally, GND would be connected directly to an
even a Pi filter made up of inductors and
analog ground plane. This plane would be separate
capacitors—all designed to essentially low-pass filter
from the ground connection for the digital
the supply, removing the high-frequency noise.
components until they are connected at the power
entry point of the system.
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